1.1 Subatomic Particles **

Question 1

protons

Answer 1

• located in nucleus of atom
• charge = 1.6 x 10^-19 C
• mass = 1 amu
• # of protons → which element

Question 2

atomic mass unit (amu)

Answer 2

• 1 amu = 1.66 x 10^-24 g
• 1 amu = mass of a proton
• atomic mass (in amu) = mass number (A)
• 1 amu = exactly 1/12 the mass of a carbon-12 atom
  
  • carbon-12 has 6p⁺ and 6n⁰ (mass of proton and neutron ≈ 1 amu)
    
    • ***mass of neutron – mass of electron ≈ mass of electron

Question 3

fundamental unit of charge (e)

Answer 3

• e = 1.6 x10^-19 Coulombs
• also denoted as +1e or +1
  
  • charge of proton = e
  • charge of electron = -e

Question 4

atomic number (Z)

Answer 4

• Z = the number of protons in an atom of an element
  
  • atomic number defines an element; if Z changes, then so does the element

Question 5

neutrons

Answer 5

• located in nucleus of atom
• mass = slightly > mass of a proton or 1 amu
• # of neutrons →isotopes

Question 6

mass number (A)

Answer 6

• mass number = # of protons + # of neutrons
  
  • elements can have varying mass numbers (isotopes)

Question 7

isotopes

Answer 7

• an element with the same # of protons (Z) but different # of neutrons (A)
  
  • isotopes have the same # of protons → exhibit similar chemical properties
• denoted as: element-mass number (Z)
  
  • ex: carbon-12 or iodine-131
• ***in nature: almost all elements exist as 2 or more isotopes

Question 8

^A_ZX

Answer 8

X = element symbol

A = mass number (p + n)

Z = atomic number (# of protonzzz)

*** A - Z = # of neutrons

*** # of electrons = # of protons (in a neutral atom)

Question 9

electrons

Answer 9

• charge = -1.6 x 10^-19 C (opposite of proton)
• mass = 1 / 2000 of a proton
  
  • ***mass is so small → not included in calculations
  • ***mass is so small → electrostatic force of attraction between proton(+) and electron(-) is far greater than gravitational force of attraction between their masses

Question 10

electrons (2)

Answer 10

• electrons move through varying energy levels (shells) surrounding the nucleus of an atom
  
  • closer to nucleus → lower energy, weaker interaction with surrounding env.
  • farther from nucleus → higher energy, stronger interaction with surrounding env.

Question 11

shells

Answer 11

• the varying distances between an electron and the nucleus of an atom
  
  • represents the different levels of electrical potential energy

Question 12

valence electrons

Answer 12

• electrons in the outermost shell (highest energy level) of an atom
  
  • determines reactivity of an atom
    
    • experience the least electrostatic pull from nucleus → higher tendency to interact w/ bonds of other atoms

Question 13

cation and anion

Answer 13

• cation: positively charged atom
  
  • due to loss of electron
• anion: negatively charged atom
  
  • due to gain of electron

Question 14

Figure 1.2 Periodic Table

Answer 14

19 = atomic number (# of protons)

39.1 = atomic weight

K = element

Question 15

Table 1.1 Subatomic Particles

Answer 15

Question 16

Figure 1.3 Various Isotopes of Hydrogen

Answer 16

Question 17

Practice Problem

Answer 17

Question 18

1.1 Concept Check: #1

Answer 18

Question 19

1.1 Concept Check: #2

Answer 19